Index: branches/pap/ppStack/src/ppStackConvolve.c
===================================================================
--- branches/pap/ppStack/src/ppStackConvolve.c	(revision 26311)
+++ branches/pap/ppStack/src/ppStackConvolve.c	(revision 26312)
@@ -117,7 +117,20 @@
                 psMetadataAddF32(options->stats, PS_LIST_TAIL, "STAMP.NUM", PS_META_DUPLICATE_OK,
                                  "Number of stamps", kernels->numStamps);
-                float norm = psMetadataLookupF32(NULL, readout->analysis, PM_SUBTRACTION_ANALYSIS_NORM);
-                psMetadataAddF32(options->stats, PS_LIST_TAIL, "KERNEL.NORM", PS_META_DUPLICATE_OK,
-                                 "Normalisation for kernel", norm);
+                {
+                    float norm = 0.0;   // Normalisation
+                    int num = 0;        // Number of instances
+                    psMetadataIterator *iter = psMetadataIteratorAlloc(readout->analysis, PS_LIST_HEAD,
+                                                                       "^" PM_SUBTRACTION_ANALYSIS_NORM "$");
+                    psMetadataItem *item = NULL;
+                    while ((item = psMetadataGetAndIncrement(iter))) {
+                        assert(item->type == PS_TYPE_F32);
+                        norm += item->data.F32;
+                        num++;
+                    }
+                    norm /= num;
+                    psFree(iter);
+                    psMetadataAddF32(options->stats, PS_LIST_TAIL, "KERNEL.NORM", PS_META_DUPLICATE_OK,
+                                     "Normalisation for kernel", norm);
+                }
                 float deconv = psMetadataLookupF32(NULL, readout->analysis,
                                                    PM_SUBTRACTION_ANALYSIS_DECONV_MAX);